Latest version of Eigen no longer needs these windows-specific changes, removing them from install help.
Latest version of Eigen no longer needs these windows-specific changes, removing them from install help.


Former-commit-id: c85f273e60378a95b87f3ae768444c32c9d5a695
shuheik/dynet,chunyang-wen/dynet,clab/cnn,clab/cnn,xunzhang/dynet,chunyang-wen/dynet,clab/dynet,shuheik/dynet,danielhers/dynet,shuheik/dynet,chunyang-wen/dynet,danielhers/dynet,danielhers/dynet,clab/dynet,danielhers/dynet,danielhers/dynet,clab/dynet,clab/cnn,chunyang-wen/dynet,xunzhang/dynet,xunzhang/dynet,clab/dynet,xunzhang/dynet,shuheik/dynet,clab/dynet,shuheik/dynet,danielhers/dynet,clab/dynet,shuheik/dynet,danielhers/dynet,clab/dynet,shuheik/dynet